There are really a lot of scams out there in the market. Be careful. Alway check their website, their communities, are they active on social media etc. Also, do you believe in their project etc. For example, I follow closely SciDex. They are creating a new type of smart contract generator for complex transactions. So that even regular businesses that need legally binding contracts can be on the blockchain. That’s improving the whole blockchain ecosystem, if you ask me.